This invention relates to gold-based dental alloys for use in dental restorations.
Gold-based alloys in dentistry were initially replaced by more economical palladium-based alloys. Recent increases in the price of palladium are making these alloys very expensive. Other economical alternatives have been nickel-based, cobalt-based and titanium-based systems. Nickel-based alloys allegedly have sensitivity concerns for some people. Cobalt-based and titanium-based alloys are difficult to process and require special care and expensive equipment.
Prior solutions to the problem have been to use metal-free ceramic/composite systems or sintered or plated copings. It is desirable to provide alloys for use in the manufacture of dental restorations having little or no palladium therein. It is further desirable that the alloys have high strength and are easily formable into dental restorations.
These and other objects and advantages are accomplished by the alloys herein having a coefficient of thermal expansion in the range from about 8 to about 18xc3x9710xe2x88x926/xc2x0 C. in the temperature range of 25-500xc2x0 C. and melting temperatures above about 800xc2x0 C. but below about 1500xc2x0 C. The alloys herein contain gold in combination with a small amount of chromium and/or tantalum. Other elements may also be included with the gold and chromium and/or tantalum to provide the necessary forming, melting, mechanical and similar properties required to manufacture the desired dental restoration. The alloys are particularly useful as substrate components for dental restorative materials including, but not limited to, orthodontic appliances, bridges, space maintainers, tooth replacement appliances, splints, crowns, partial crowns, dentures, posts, teeth, jackets, inlays, onlays, facing, veneers, facets, implants, abutments, cylinders, and connectors. The substrate may be defined as a main component of the dental restoration having one or more layers of material thereon, or as the complete restoration with no other material thereon.